A brominated polystyrene having a degree of polymerization of approximately 2,000 when used in high impact polystyrene provides excellent flame retardancy and stability but has a very negative effect on key physical properties such as impact strength. This effect is generally unacceptable.
U.S. Pat. No. 3,075,944 relates to flame retardant compositions containing polyolefins which can be made by substituting a diaromatic or an aromatic-aliphatic ether containing at least three bromine atoms.
U.S. Pat. No. 3,830,766 relates to flame-proofing acrylonitrile-butadiene-styrene (ABS)polymers by incorporating therein an aromatic bromine compound, antimony trioxide or antimony oxychloride and optionally an organo chlorine compound.
U.S. Pat. No. 3,897,373 relates to thermoplastic molding compositions based on styrene polymers and flameproofed with an organic bromine compound. They contain a synergistic azo compound and may be converted to self-extinguishing shaped articles or profiles.
U.S. Pat. No. 3,943,195 relates to a thermoplastic molding material based on styrene polymers and olefin polymers which have been flameproofed with an organic bromine compound. Brominated oligomers or polymers of dialkylbenzenes, trialkylbenzenes or tetraalkylbenzenes serve as flameproofing agents. The molding material may be processed into self-extinguishing moldings.
U.S. Pat. No. 3,962,164 relates to flame-proofing acrylonitrile-butadiene-styrene (ABS) polymers, incorporating therein certain mono- and diphenyl aromatic bromine compounds such as octabromodiphenyl, antimony trioxide, or antimony oxychloride and optionally an organo chlorine compound.
U.S. Pat. No. 4,049,622 relates to thermoplastic molding compositions based on styrene polymers, preferably formed styrene polymers, which have been flameproofed with an organic bromine compound.
U.S. Pat. No. 4,074,032 relates to a process for the manufacture of heat-stable, brominated oligostyrenes by brominating selectively hydrogenated oligostyrenes in halogenated solvents in the presence of Lewis acids at from about minus 25.degree. C. to 20.degree. C. The brominated oligomers are highly heat-stable and can be processed, by themselves or as components of mixtures with other thermoplastics, to give various shaped articles.
U.S. Pat. No. 4,107,231 relates to flame-proofed linear polyesters containing, as flameproofing agents, halogenated oligomeric styrenes and synergistic compounds.
U.S. Pat. No. 4,137,212 relates to a flame-proofed nylon molding composition which can be processed by thermoplastic methods and which contains, as the flameproofing agent, from 5 to 30 percent by weight of brominated styrene oligomers and a synergistic metal oxide. The composition may be used for the manufacture of injection moldings for the electrical industry.
U.S. Pat. No. 4,143,221 relates to styrene polymers or copolymers containing bromine which are manufactured by cationic polymerization of the monomer, or of the monomer plus a copolymerizable monomer of the isobutylene or nuclear-alkylated styrene type, in an organic solvent in the presence of a Lewis acid catalyst. Bromine is then added to the solution without first working up the latter. The catalyst used for the bromination is the same as that used for the polymerization. If necessary, fresh catalyst may be added before the bromination. After completion of the bromination, the reaction solution is extracted with water until it is bromide-free, and the solvent, generally a halohydrocarbon, is then stripped off. Products containing up to about 80 percent by weight of bromine may be obtained. They have a pale yellowish color and exhibit no significant decomposition up to 340.degree. C. They may be used as flameproofing agents for thermoplastics.
U.S. Pat. No. 4,151,223 relates to fibers and filaments of linear thermoplastic polyesters, containing halogen-containing flameproofing agents and synergistic agents therefor, in which the flameproofing agents are chlorinated and/or brominated oligomeric styrenes. The fibers and filaments of the invention are used for the manufacture of textiles of low flammability.
U.S. Pat. No. 4,200,702 relates to thermoplastic molding compositions based on rubber-modified styrene-acrylonitrile copolymers containing a halogenated styrene oligomer as the effective flameproofing agent which is sufficiently heat-stable, does not interfere with processing on conventional machinery, does not corrode or cause coatings on such machinery, and has virtually no adverse effect on the impact strength of the polymers. The flameproofing agent as a rule has a degree of polymerization of from 3 to 200 and can be incorporated into the polymer by conventional methods; the polymer may or may not contain additional synergistic agents and processing auxiliaries, which are incorporated in the conventional manner and in the conventional amounts.
U.S. Pat. No. 4,360,455 relates to a mixture of brominated oligomeric polystyrenes having a degree of polymerization of from 3 to 400, and low molecular weight brominated aromatic compounds of the diphenyl ether type which are obtained by polymerizing the non-brominated starting materials, in a halohydrocarbon solvent, using a Lewis acid catalyst. The reaction mixture is then brominated and extracted with water to remove hydrogen bromine and catalyst, and the solvent and volatile constituents are separated from the product. The bromination is carried out at from minus 30.degree. C. to 130.degree. C. The final mixtures have a low melt viscosity and are therefore particularly suitable for incorporation, as a flame-proofing agent, into thermoplastics.
U.S. Pat. No. 4,352,909, to Barda et al relates to a process for producing a trihalogenated polystyrene flame retardant for synthetic resins, whereby high molecular weight polystyrene is reacted with bromine chloride in a chlorinated hydrocarbon solvent, under substantially anhydrous conditions, in the presence of a catalytic amount of a Lewis acid.
German Patentschrift 151,075 relates to self-extinguishing polystyrene compositions containing brominated oligomers of alpha methyl-styrene as flame retardants with minimum loss of mechanical properties. The oligomer contains from 40 to 70 weight percent ring-bound bromine and has a molecular weight of from about 1,000 to about 5,000.